mirror of
https://github.com/TelegramMessenger/Telegram-iOS.git
synced 2026-05-21 18:20:41 +00:00
Ilya Laktyushin
1614 lines
64 KiB
Swift
1614 lines
64 KiB
Swift
//
|
|
// Created by Mike Griebling on 2022-12-31.
|
|
// Translated from an Objective-C implementation by Kostub Deshmukh.
|
|
//
|
|
// This software may be modified and distributed under the terms of the
|
|
// MIT license. See the LICENSE file for details.
|
|
//
|
|
|
|
import Foundation
|
|
|
|
/** `MTMathListBuilder` is a class for parsing LaTeX into an `MTMathList` that
|
|
can be rendered and processed mathematically.
|
|
*/
|
|
struct MTEnvProperties {
|
|
var envName: String?
|
|
var ended: Bool
|
|
var numRows: Int
|
|
var alignment: MTColumnAlignment? // Optional alignment for starred matrix environments
|
|
|
|
init(name: String?, alignment: MTColumnAlignment? = nil) {
|
|
self.envName = name
|
|
self.numRows = 0
|
|
self.ended = false
|
|
self.alignment = alignment
|
|
}
|
|
}
|
|
|
|
/**
|
|
The error encountered when parsing a LaTeX string.
|
|
|
|
The `code` in the `NSError` is one of the following indicating why the LaTeX string
|
|
could not be parsed.
|
|
*/
|
|
enum MTParseErrors:Int {
|
|
/// The braces { } do not match.
|
|
case mismatchBraces = 1
|
|
/// A command in the string is not recognized.
|
|
case invalidCommand
|
|
/// An expected character such as ] was not found.
|
|
case characterNotFound
|
|
/// The \left or \right command was not followed by a delimiter.
|
|
case missingDelimiter
|
|
/// The delimiter following \left or \right was not a valid delimiter.
|
|
case invalidDelimiter
|
|
/// There is no \right corresponding to the \left command.
|
|
case missingRight
|
|
/// There is no \left corresponding to the \right command.
|
|
case missingLeft
|
|
/// The environment given to the \begin command is not recognized
|
|
case invalidEnv
|
|
/// A command is used which is only valid inside a \begin,\end environment
|
|
case missingEnv
|
|
/// There is no \begin corresponding to the \end command.
|
|
case missingBegin
|
|
/// There is no \end corresponding to the \begin command.
|
|
case missingEnd
|
|
/// The number of columns do not match the environment
|
|
case invalidNumColumns
|
|
/// Internal error, due to a programming mistake.
|
|
case internalError
|
|
/// Limit control applied incorrectly
|
|
case invalidLimits
|
|
}
|
|
|
|
let MTParseError = "ParseError"
|
|
|
|
/** `MTMathListBuilder` is a class for parsing LaTeX into an `MTMathList` that
|
|
can be rendered and processed mathematically.
|
|
*/
|
|
public struct MTMathListBuilder {
|
|
/// The math mode determines rendering style (inline vs display)
|
|
enum MathMode {
|
|
/// Display style - larger operators, limits above/below (e.g., $$...$$, \[...\])
|
|
case display
|
|
/// Inline/text style - compact operators, limits to the side (e.g., $...$, \(...\))
|
|
case inline
|
|
|
|
/// Convert MathMode to MTLineStyle for rendering
|
|
func toLineStyle() -> MTLineStyle {
|
|
switch self {
|
|
case .display:
|
|
return .display
|
|
case .inline:
|
|
return .text
|
|
}
|
|
}
|
|
}
|
|
|
|
var string: String
|
|
var currentCharIndex: String.Index
|
|
var currentInnerAtom: MTInner?
|
|
var currentEnv: MTEnvProperties?
|
|
var currentFontStyle:MTFontStyle
|
|
var spacesAllowed:Bool
|
|
var mathMode: MathMode = .display
|
|
|
|
/** Contains any error that occurred during parsing. */
|
|
var error:NSError?
|
|
|
|
// MARK: - Character-handling routines
|
|
|
|
var hasCharacters: Bool { currentCharIndex < string.endIndex }
|
|
|
|
// gets the next character and increments the index
|
|
mutating func getNextCharacter() -> Character {
|
|
assert(self.hasCharacters, "Retrieving character at index \(self.currentCharIndex) beyond length \(self.string.count)")
|
|
let ch = string[currentCharIndex]
|
|
currentCharIndex = string.index(after: currentCharIndex)
|
|
return ch
|
|
}
|
|
|
|
mutating func unlookCharacter() {
|
|
assert(currentCharIndex > string.startIndex, "Unlooking when at the first character.")
|
|
if currentCharIndex > string.startIndex {
|
|
currentCharIndex = string.index(before: currentCharIndex)
|
|
}
|
|
}
|
|
|
|
// Peek at next command without consuming it (for \not lookahead)
|
|
mutating func peekNextCommand() -> String {
|
|
let savedIndex = currentCharIndex
|
|
skipSpaces()
|
|
|
|
guard hasCharacters else {
|
|
currentCharIndex = savedIndex
|
|
return ""
|
|
}
|
|
|
|
let char = getNextCharacter()
|
|
let command: String
|
|
|
|
if char == "\\" {
|
|
command = readCommand()
|
|
} else {
|
|
command = ""
|
|
}
|
|
|
|
// Restore position
|
|
currentCharIndex = savedIndex
|
|
return command
|
|
}
|
|
|
|
// Consume the next command (after peeking)
|
|
mutating func consumeNextCommand() {
|
|
skipSpaces()
|
|
|
|
guard hasCharacters else { return }
|
|
|
|
let char = getNextCharacter()
|
|
if char == "\\" {
|
|
_ = readCommand()
|
|
}
|
|
}
|
|
|
|
|
|
|
|
mutating func expectCharacter(_ ch: Character) -> Bool {
|
|
MTAssertNotSpace(ch)
|
|
self.skipSpaces()
|
|
|
|
if self.hasCharacters {
|
|
let nextChar = self.getNextCharacter()
|
|
MTAssertNotSpace(nextChar)
|
|
if nextChar == ch {
|
|
return true
|
|
} else {
|
|
self.unlookCharacter()
|
|
return false
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
public static let spaceToCommands: [CGFloat: String] = [
|
|
3 : ",",
|
|
4 : ">",
|
|
5 : ";",
|
|
(-3) : "!",
|
|
18 : "quad",
|
|
36 : "qquad",
|
|
]
|
|
|
|
public static let styleToCommands: [MTLineStyle: String] = [
|
|
.display: "displaystyle",
|
|
.text: "textstyle",
|
|
.script: "scriptstyle",
|
|
.scriptOfScript: "scriptscriptstyle"
|
|
]
|
|
|
|
// Comprehensive mapping of \not command combinations to Unicode negated symbols
|
|
public static let notCombinations: [String: String] = [
|
|
// Primary targets (user requested)
|
|
"equiv": "\u{2262}", // ≢ Not equivalent
|
|
"subset": "\u{2284}", // ⊄ Not subset
|
|
"in": "\u{2209}", // ∉ Not element of
|
|
|
|
// Additional standard negations
|
|
"sim": "\u{2241}", // ≁ Not similar
|
|
"approx": "\u{2249}", // ≉ Not approximately equal
|
|
"cong": "\u{2247}", // ≇ Not congruent
|
|
"parallel": "\u{2226}", // ∦ Not parallel
|
|
"subseteq": "\u{2288}", // ⊈ Not subset or equal
|
|
"supset": "\u{2285}", // ⊅ Not superset
|
|
"supseteq": "\u{2289}", // ⊉ Not superset or equal
|
|
"=": "\u{2260}", // ≠ Not equal (alternative to \neq)
|
|
]
|
|
|
|
/// Delimiter sizing commands with their size multipliers (relative to font size).
|
|
/// Values based on standard TeX: at 10pt, \big=8.5pt, \Big=11.5pt, \bigg=14.5pt, \Bigg=17.5pt
|
|
/// These translate to approximately 0.85x, 1.15x, 1.45x, 1.75x of font size.
|
|
/// We use slightly larger values to ensure visible size differences.
|
|
public static let delimiterSizeCommands: [String: CGFloat] = [
|
|
// Basic sizing commands
|
|
"big": 1.0,
|
|
"Big": 1.4,
|
|
"bigg": 1.8,
|
|
"Bigg": 2.2,
|
|
// Left variants (same sizes, just semantic distinction in LaTeX)
|
|
"bigl": 1.0,
|
|
"Bigl": 1.4,
|
|
"biggl": 1.8,
|
|
"Biggl": 2.2,
|
|
// Right variants
|
|
"bigr": 1.0,
|
|
"Bigr": 1.4,
|
|
"biggr": 1.8,
|
|
"Biggr": 2.2,
|
|
// Middle variants (used between delimiters)
|
|
"bigm": 1.0,
|
|
"Bigm": 1.4,
|
|
"biggm": 1.8,
|
|
"Biggm": 2.2,
|
|
]
|
|
|
|
init(string: String) {
|
|
self.error = nil
|
|
self.string = string
|
|
self.currentCharIndex = string.startIndex
|
|
self.currentFontStyle = .defaultStyle
|
|
self.spacesAllowed = false
|
|
}
|
|
|
|
// MARK: - Delimiter Detection
|
|
|
|
/// Detects and strips LaTeX math delimiters from the input string.
|
|
/// Returns the cleaned content and the detected math mode.
|
|
/// Supports: $...$ \(...\) $$...$$ \[...\] and environments
|
|
func detectAndStripDelimiters(from str: String) -> (String, MathMode) {
|
|
let trimmed = str.trimmingCharacters(in: .whitespacesAndNewlines)
|
|
|
|
// Check display delimiters first (more specific patterns)
|
|
|
|
// \[...\] - LaTeX display math
|
|
if trimmed.hasPrefix("\\[") && trimmed.hasSuffix("\\]") && trimmed.count > 4 {
|
|
let content = String(trimmed.dropFirst(2).dropLast(2))
|
|
return (content, .display)
|
|
}
|
|
|
|
// $$...$$ - TeX display math (check before single $)
|
|
if trimmed.hasPrefix("$$") && trimmed.hasSuffix("$$") && trimmed.count > 4 {
|
|
let content = String(trimmed.dropFirst(2).dropLast(2))
|
|
return (content, .display)
|
|
}
|
|
|
|
// Check inline delimiters
|
|
|
|
// \(...\) - LaTeX inline math
|
|
if trimmed.hasPrefix("\\(") && trimmed.hasSuffix("\\)") && trimmed.count > 4 {
|
|
let content = String(trimmed.dropFirst(2).dropLast(2))
|
|
return (content, .inline)
|
|
}
|
|
|
|
// $...$ - TeX inline math (must check after $$)
|
|
if trimmed.hasPrefix("$") && trimmed.hasSuffix("$") && trimmed.count > 2 && !trimmed.hasPrefix("$$") {
|
|
let content = String(trimmed.dropFirst(1).dropLast(1))
|
|
return (content, .inline)
|
|
}
|
|
|
|
// Check if it's an environment (\begin{...}\end{...})
|
|
// These are handled by existing logic and are display mode by default
|
|
if trimmed.hasPrefix("\\begin{") {
|
|
return (str, .display)
|
|
}
|
|
|
|
// No delimiters found - default to display mode (current behavior for backward compatibility)
|
|
return (str, .display)
|
|
}
|
|
|
|
// MARK: - MTMathList builder functions
|
|
|
|
/// Builds a mathlist from the internal `string`. Returns nil if there is an error.
|
|
public mutating func build() -> MTMathList? {
|
|
// Detect and strip delimiters, updating the string and mode
|
|
let (cleanedString, mode) = detectAndStripDelimiters(from: self.string)
|
|
self.string = cleanedString
|
|
self.currentCharIndex = cleanedString.startIndex
|
|
self.mathMode = mode
|
|
|
|
// If inline mode, we could optionally prepend a \textstyle command
|
|
// to force inline rendering of operators. For now, just track the mode.
|
|
|
|
let list = self.buildInternal(false)
|
|
if self.hasCharacters && error == nil {
|
|
self.setError(.mismatchBraces, message: "Mismatched braces: \(self.string)")
|
|
return nil
|
|
}
|
|
if error != nil {
|
|
return nil
|
|
}
|
|
|
|
// Note: For inline mode, we insert \textstyle to match LaTeX behavior.
|
|
// However, fractionStyle() has been modified to keep fractions at the
|
|
// same font size in both display and text modes (not one level smaller).
|
|
// Large operators show limits above/below in text style due to the updated
|
|
// condition in makeLargeOp() that checks both .display and .text styles.
|
|
if mode == .inline && list != nil && !list!.atoms.isEmpty {
|
|
// Prepend \textstyle to force inline rendering
|
|
let styleAtom = MTMathStyle(style: .text)
|
|
list!.atoms.insert(styleAtom, at: 0)
|
|
}
|
|
|
|
return list
|
|
}
|
|
|
|
/** Construct a math list from a given string. If there is parse error, returns
|
|
nil. To retrieve the error use the function `MTMathListBuilder.build(fromString:error:)`.
|
|
*/
|
|
public static func build(fromString string: String) -> MTMathList? {
|
|
var builder = MTMathListBuilder(string: string)
|
|
return builder.build()
|
|
}
|
|
|
|
/** Construct a math list from a given string. If there is an error while
|
|
constructing the string, this returns nil. The error is returned in the
|
|
`error` parameter.
|
|
*/
|
|
public static func build(fromString string: String, error:inout NSError?) -> MTMathList? {
|
|
var builder = MTMathListBuilder(string: string)
|
|
let output = builder.build()
|
|
if builder.error != nil {
|
|
error = builder.error
|
|
return nil
|
|
}
|
|
return output
|
|
}
|
|
|
|
/** Construct a math list from a given string and return the detected style.
|
|
This method detects LaTeX delimiters like \[...\], $$...$$, $...$, \(...\)
|
|
and returns the appropriate rendering style (.display or .text).
|
|
|
|
If there is a parse error, returns nil for the MathList.
|
|
|
|
- Parameter string: The LaTeX string to parse
|
|
- Returns: A tuple containing the parsed MathList and the detected MTLineStyle
|
|
*/
|
|
public static func buildWithStyle(fromString string: String) -> (mathList: MTMathList?, style: MTLineStyle) {
|
|
var builder = MTMathListBuilder(string: string)
|
|
let mathList = builder.build()
|
|
let style = builder.mathMode.toLineStyle()
|
|
return (mathList, style)
|
|
}
|
|
|
|
/** Construct a math list from a given string and return the detected style.
|
|
This method detects LaTeX delimiters like \[...\], $$...$$, $...$, \(...\)
|
|
and returns the appropriate rendering style (.display or .text).
|
|
|
|
If there is an error while constructing the string, this returns nil for the MathList.
|
|
The error is returned in the `error` parameter.
|
|
|
|
- Parameters:
|
|
- string: The LaTeX string to parse
|
|
- error: An inout parameter that will contain any parse error
|
|
- Returns: A tuple containing the parsed MathList and the detected MTLineStyle
|
|
*/
|
|
public static func buildWithStyle(fromString string: String, error: inout NSError?) -> (mathList: MTMathList?, style: MTLineStyle) {
|
|
var builder = MTMathListBuilder(string: string)
|
|
let output = builder.build()
|
|
let style = builder.mathMode.toLineStyle()
|
|
if builder.error != nil {
|
|
error = builder.error
|
|
return (nil, style)
|
|
}
|
|
return (output, style)
|
|
}
|
|
|
|
public mutating func buildInternal(_ oneCharOnly: Bool) -> MTMathList? {
|
|
self.buildInternal(oneCharOnly, stopChar: nil)
|
|
}
|
|
|
|
public mutating func buildInternal(_ oneCharOnly: Bool, stopChar stop: Character?) -> MTMathList? {
|
|
let list = MTMathList()
|
|
assert(!(oneCharOnly && stop != nil), "Cannot set both oneCharOnly and stopChar.")
|
|
var prevAtom: MTMathAtom? = nil
|
|
while self.hasCharacters {
|
|
if error != nil { return nil } // If there is an error thus far then bail out.
|
|
|
|
var atom: MTMathAtom? = nil
|
|
let char = self.getNextCharacter()
|
|
|
|
if oneCharOnly {
|
|
if char == "^" || char == "}" || char == "_" || char == "&" {
|
|
// this is not the character we are looking for.
|
|
// They are meant for the caller to look at.
|
|
self.unlookCharacter()
|
|
return list
|
|
}
|
|
}
|
|
// If there is a stop character, keep scanning 'til we find it
|
|
if stop != nil && char == stop! {
|
|
return list
|
|
}
|
|
|
|
if char == "^" {
|
|
assert(!oneCharOnly, "This should have been handled before")
|
|
if (prevAtom == nil || prevAtom!.superScript != nil || !prevAtom!.isScriptAllowed()) {
|
|
// If there is no previous atom, or if it already has a superscript
|
|
// or if scripts are not allowed for it, then add an empty node.
|
|
prevAtom = MTMathAtom(type: .ordinary, value: "")
|
|
list.add(prevAtom!)
|
|
}
|
|
// this is a superscript for the previous atom
|
|
// note: if the next char is the stopChar it will be consumed by the ^ and so it doesn't count as stop
|
|
prevAtom!.superScript = self.buildInternal(true)
|
|
continue
|
|
} else if char == "_" {
|
|
assert(!oneCharOnly, "This should have been handled before")
|
|
if (prevAtom == nil || prevAtom!.subScript != nil || !prevAtom!.isScriptAllowed()) {
|
|
// If there is no previous atom, or if it already has a subcript
|
|
// or if scripts are not allowed for it, then add an empty node.
|
|
prevAtom = MTMathAtom(type: .ordinary, value: "")
|
|
list.add(prevAtom!)
|
|
}
|
|
// this is a subscript for the previous atom
|
|
// note: if the next char is the stopChar it will be consumed by the _ and so it doesn't count as stop
|
|
prevAtom!.subScript = self.buildInternal(true)
|
|
continue
|
|
} else if char == "{" {
|
|
// this puts us in a recursive routine, and sets oneCharOnly to false and no stop character
|
|
if let subList = self.buildInternal(false, stopChar: "}") {
|
|
prevAtom = subList.atoms.last
|
|
list.append(subList)
|
|
if oneCharOnly {
|
|
return list
|
|
}
|
|
}
|
|
continue
|
|
} else if char == "}" {
|
|
// \ means a command
|
|
assert(!oneCharOnly, "This should have been handled before")
|
|
assert(stop == nil, "This should have been handled before")
|
|
// Special case: } terminates implicit table (envName == nil) created by \\
|
|
// This happens when \\ is used inside braces: \substack{a \\ b}
|
|
if self.currentEnv != nil && self.currentEnv!.envName == nil {
|
|
// Mark environment as ended, don't consume the }
|
|
self.currentEnv!.ended = true
|
|
return list
|
|
}
|
|
// We encountered a closing brace when there is no stop set, that means there was no
|
|
// corresponding opening brace.
|
|
self.setError(.mismatchBraces, message:"Mismatched braces.")
|
|
return nil
|
|
} else if char == "\\" {
|
|
let command = readCommand()
|
|
let done = stopCommand(command, list:list, stopChar:stop)
|
|
if done != nil {
|
|
return done
|
|
} else if error != nil {
|
|
return nil
|
|
}
|
|
if self.applyModifier(command, atom:prevAtom) {
|
|
continue
|
|
}
|
|
|
|
if let fontStyle = MTMathAtomFactory.fontStyleWithName(command) {
|
|
let oldSpacesAllowed = spacesAllowed
|
|
// Text has special consideration where it allows spaces without escaping.
|
|
spacesAllowed = command == "text"
|
|
let oldFontStyle = currentFontStyle
|
|
currentFontStyle = fontStyle
|
|
if let sublist = self.buildInternal(true) {
|
|
// Restore the font style.
|
|
currentFontStyle = oldFontStyle
|
|
spacesAllowed = oldSpacesAllowed
|
|
|
|
prevAtom = sublist.atoms.last
|
|
list.append(sublist)
|
|
if oneCharOnly {
|
|
return list
|
|
}
|
|
}
|
|
continue
|
|
}
|
|
atom = self.atomForCommand(command)
|
|
if atom == nil {
|
|
// this was an unknown command,
|
|
// we flag an error and return
|
|
// (note setError will not set the error if there is already one, so we flag internal error
|
|
// in the odd case that an _error is not set.
|
|
self.setError(.internalError, message:"Internal error")
|
|
return nil
|
|
}
|
|
} else if char == "&" {
|
|
// used for column separation in tables
|
|
assert(!oneCharOnly, "This should have been handled before")
|
|
if self.currentEnv != nil {
|
|
return list
|
|
} else {
|
|
// Create a new table with the current list and a default env
|
|
if let table = self.buildTable(env: nil, firstList: list, isRow: false) {
|
|
return MTMathList(atom: table)
|
|
} else {
|
|
return nil
|
|
}
|
|
}
|
|
} else if spacesAllowed && char == " " {
|
|
// If spaces are allowed then spaces do not need escaping with a \ before being used.
|
|
atom = MTMathAtomFactory.atom(forLatexSymbol: " ")
|
|
} else {
|
|
atom = MTMathAtomFactory.atom(forCharacter: char)
|
|
if atom == nil {
|
|
// Not a recognized character in standard math mode
|
|
// In text mode (spacesAllowed && roman style), accept any Unicode character for fallback font support
|
|
// This enables Chinese, Japanese, Korean, emoji, etc. in \text{} commands
|
|
if spacesAllowed && currentFontStyle == .roman {
|
|
atom = MTMathAtom(type: .ordinary, value: String(char))
|
|
} else {
|
|
// In math mode or non-text commands, skip unrecognized characters
|
|
continue
|
|
}
|
|
}
|
|
}
|
|
|
|
assert(atom != nil, "Atom shouldn't be nil")
|
|
atom?.fontStyle = currentFontStyle
|
|
// If this is an accent atom (e.g., from an accented character like "é"),
|
|
// propagate the font style to the inner list atoms that don't already have
|
|
// an explicit font style. This handles Unicode accented characters which are
|
|
// converted to accents by atom(fromAccentedCharacter:) without font style context.
|
|
// We only set font style on atoms with .defaultStyle to avoid overriding
|
|
// explicit font style commands like \textbf inside accents.
|
|
if let accent = atom as? MTAccent, let innerList = accent.innerList {
|
|
for innerAtom in innerList.atoms {
|
|
if innerAtom.fontStyle == .defaultStyle {
|
|
innerAtom.fontStyle = currentFontStyle
|
|
}
|
|
}
|
|
}
|
|
list.add(atom)
|
|
prevAtom = atom
|
|
|
|
if oneCharOnly {
|
|
return list
|
|
}
|
|
}
|
|
if stop != nil {
|
|
if stop == "}" {
|
|
// We did not find a corresponding closing brace.
|
|
self.setError(.mismatchBraces, message:"Missing closing brace")
|
|
} else {
|
|
// we never found our stop character
|
|
let errorMessage = "Expected character not found: \(stop!)"
|
|
self.setError(.characterNotFound, message:errorMessage)
|
|
}
|
|
}
|
|
return list
|
|
}
|
|
|
|
|
|
// MARK: - MTMathList to LaTeX conversion
|
|
|
|
/// This converts the MTMathList to LaTeX.
|
|
public static func mathListToString(_ ml: MTMathList?) -> String {
|
|
var str = ""
|
|
var currentfontStyle = MTFontStyle.defaultStyle
|
|
if let atomList = ml {
|
|
for atom in atomList.atoms {
|
|
if currentfontStyle != atom.fontStyle {
|
|
if currentfontStyle != .defaultStyle {
|
|
str += "}"
|
|
}
|
|
if atom.fontStyle != .defaultStyle {
|
|
let fontStyleName = MTMathAtomFactory.fontNameForStyle(atom.fontStyle)
|
|
str += "\\\(fontStyleName){"
|
|
}
|
|
currentfontStyle = atom.fontStyle
|
|
}
|
|
if atom.type == .fraction {
|
|
if let frac = atom as? MTFraction {
|
|
if frac.isContinuedFraction {
|
|
// Generate \cfrac with optional alignment
|
|
if frac.alignment != "c" {
|
|
str += "\\cfrac[\(frac.alignment)]{\(mathListToString(frac.numerator!))}{\(mathListToString(frac.denominator!))}"
|
|
} else {
|
|
str += "\\cfrac{\(mathListToString(frac.numerator!))}{\(mathListToString(frac.denominator!))}"
|
|
}
|
|
} else if frac.hasRule {
|
|
str += "\\frac{\(mathListToString(frac.numerator!))}{\(mathListToString(frac.denominator!))}"
|
|
} else {
|
|
let command: String
|
|
if frac.leftDelimiter.isEmpty && frac.rightDelimiter.isEmpty {
|
|
command = "atop"
|
|
} else if frac.leftDelimiter == "(" && frac.rightDelimiter == ")" {
|
|
command = "choose"
|
|
} else if frac.leftDelimiter == "{" && frac.rightDelimiter == "}" {
|
|
command = "brace"
|
|
} else if frac.leftDelimiter == "[" && frac.rightDelimiter == "]" {
|
|
command = "brack"
|
|
} else {
|
|
command = "atopwithdelims\(frac.leftDelimiter)\(frac.rightDelimiter)"
|
|
}
|
|
str += "{\(mathListToString(frac.numerator!)) \\\(command) \(mathListToString(frac.denominator!))}"
|
|
}
|
|
}
|
|
} else if atom.type == .radical {
|
|
str += "\\sqrt"
|
|
if let rad = atom as? MTRadical {
|
|
if rad.degree != nil {
|
|
str += "[\(mathListToString(rad.degree!))]"
|
|
}
|
|
str += "{\(mathListToString(rad.radicand!))}"
|
|
}
|
|
} else if atom.type == .inner {
|
|
if let inner = atom as? MTInner {
|
|
if inner.leftBoundary != nil || inner.rightBoundary != nil {
|
|
if inner.leftBoundary != nil {
|
|
str += "\\left\(delimToString(delim: inner.leftBoundary!)) "
|
|
} else {
|
|
str += "\\left. "
|
|
}
|
|
|
|
str += mathListToString(inner.innerList!)
|
|
|
|
if inner.rightBoundary != nil {
|
|
str += "\\right\(delimToString(delim: inner.rightBoundary!)) "
|
|
} else {
|
|
str += "\\right. "
|
|
}
|
|
} else {
|
|
str += "{\(mathListToString(inner.innerList!))}"
|
|
}
|
|
}
|
|
} else if atom.type == .table {
|
|
if let table = atom as? MTMathTable {
|
|
if !table.environment.isEmpty {
|
|
str += "\\begin{\(table.environment)}"
|
|
}
|
|
|
|
for i in 0..<table.numRows {
|
|
let row = table.cells[i]
|
|
for j in 0..<row.count {
|
|
let cell = row[j]
|
|
if table.environment == "matrix" {
|
|
if cell.atoms.count >= 1 && cell.atoms[0].type == .style {
|
|
// remove first atom
|
|
cell.atoms.removeFirst()
|
|
}
|
|
}
|
|
if table.environment == "eqalign" || table.environment == "aligned" || table.environment == "split" {
|
|
if j == 1 && cell.atoms.count >= 1 && cell.atoms[0].type == .ordinary && cell.atoms[0].nucleus.count == 0 {
|
|
// remove empty nucleus added for spacing
|
|
cell.atoms.removeFirst()
|
|
}
|
|
}
|
|
str += mathListToString(cell)
|
|
if j < row.count - 1 {
|
|
str += "&"
|
|
}
|
|
}
|
|
if i < table.numRows - 1 {
|
|
str += "\\\\ "
|
|
}
|
|
}
|
|
if !table.environment.isEmpty {
|
|
str += "\\end{\(table.environment)}"
|
|
}
|
|
}
|
|
} else if atom.type == .overline {
|
|
if let overline = atom as? MTOverLine {
|
|
str += "\\overline"
|
|
str += "{\(mathListToString(overline.innerList!))}"
|
|
}
|
|
} else if atom.type == .underline {
|
|
if let underline = atom as? MTUnderLine {
|
|
str += "\\underline"
|
|
str += "{\(mathListToString(underline.innerList!))}"
|
|
}
|
|
} else if atom.type == .accent {
|
|
if let accent = atom as? MTAccent {
|
|
str += "\\\(MTMathAtomFactory.accentName(accent)!){\(mathListToString(accent.innerList!))}"
|
|
}
|
|
} else if atom.type == .largeOperator {
|
|
let op = atom as! MTLargeOperator
|
|
let command = MTMathAtomFactory.latexSymbolName(for: atom)
|
|
let originalOp = MTMathAtomFactory.atom(forLatexSymbol: command!) as! MTLargeOperator
|
|
str += "\\\(command!) "
|
|
if originalOp.limits != op.limits {
|
|
if op.limits {
|
|
str += "\\limits "
|
|
} else {
|
|
str += "\\nolimits "
|
|
}
|
|
}
|
|
} else if atom.type == .space {
|
|
if let space = atom as? MTMathSpace {
|
|
if let command = Self.spaceToCommands[space.space] {
|
|
str += "\\\(command) "
|
|
} else {
|
|
str += String(format: "\\mkern%.1fmu", space.space)
|
|
}
|
|
}
|
|
} else if atom.type == .style {
|
|
if let style = atom as? MTMathStyle {
|
|
if let command = Self.styleToCommands[style.style] {
|
|
str += "\\\(command) "
|
|
}
|
|
}
|
|
} else if atom.nucleus.isEmpty {
|
|
str += "{}"
|
|
} else if atom.nucleus == "\u{2236}" {
|
|
// math colon
|
|
str += ":"
|
|
} else if atom.nucleus == "\u{2212}" {
|
|
// math minus
|
|
str += "-"
|
|
} else {
|
|
if let command = MTMathAtomFactory.latexSymbolName(for: atom) {
|
|
str += "\\\(command) "
|
|
} else {
|
|
str += "\(atom.nucleus)"
|
|
}
|
|
}
|
|
|
|
if atom.superScript != nil {
|
|
str += "^{\(mathListToString(atom.superScript!))}"
|
|
}
|
|
|
|
if atom.subScript != nil {
|
|
str += "_{\(mathListToString(atom.subScript!))}"
|
|
}
|
|
}
|
|
}
|
|
if currentfontStyle != .defaultStyle {
|
|
str += "}"
|
|
}
|
|
return str
|
|
}
|
|
|
|
public static func delimToString(delim: MTMathAtom) -> String {
|
|
if let command = MTMathAtomFactory.getDelimiterName(of: delim) {
|
|
let singleChars = [ "(", ")", "[", "]", "<", ">", "|", ".", "/"]
|
|
if singleChars.contains(command) {
|
|
return command
|
|
} else if command == "||" {
|
|
return "\\|"
|
|
} else {
|
|
return "\\\(command)"
|
|
}
|
|
}
|
|
return ""
|
|
}
|
|
|
|
mutating func atomForCommand(_ command:String) -> MTMathAtom? {
|
|
if let atom = MTMathAtomFactory.atom(forLatexSymbol: command) {
|
|
return atom
|
|
}
|
|
if let accent = MTMathAtomFactory.accent(withName: command) {
|
|
// The command is an accent
|
|
accent.innerList = self.buildInternal(true)
|
|
return accent;
|
|
} else if command == "frac" {
|
|
// A fraction command has 2 arguments
|
|
let frac = MTFraction()
|
|
frac.numerator = self.buildInternal(true)
|
|
frac.denominator = self.buildInternal(true)
|
|
return frac;
|
|
} else if command == "cfrac" {
|
|
// A continued fraction command with optional alignment and 2 arguments
|
|
let frac = MTFraction()
|
|
frac.isContinuedFraction = true
|
|
|
|
// Parse optional alignment parameter [l], [r], [c]
|
|
skipSpaces()
|
|
if hasCharacters && string[currentCharIndex] == "[" {
|
|
_ = getNextCharacter() // consume '['
|
|
if hasCharacters {
|
|
let alignmentChar = getNextCharacter()
|
|
if alignmentChar == "l" || alignmentChar == "r" || alignmentChar == "c" {
|
|
frac.alignment = String(alignmentChar)
|
|
}
|
|
}
|
|
// Consume closing ']'
|
|
if hasCharacters && string[currentCharIndex] == "]" {
|
|
_ = getNextCharacter()
|
|
}
|
|
}
|
|
|
|
frac.numerator = self.buildInternal(true)
|
|
frac.denominator = self.buildInternal(true)
|
|
return frac;
|
|
} else if command == "dfrac" {
|
|
// Display-style fraction command has 2 arguments
|
|
let frac = MTFraction()
|
|
let numerator = self.buildInternal(true)
|
|
let denominator = self.buildInternal(true)
|
|
|
|
// Prepend \displaystyle to force display mode rendering
|
|
let displayStyle = MTMathStyle(style: .display)
|
|
numerator?.insert(displayStyle, at: 0)
|
|
denominator?.insert(displayStyle, at: 0)
|
|
|
|
frac.numerator = numerator
|
|
frac.denominator = denominator
|
|
return frac;
|
|
} else if command == "tfrac" {
|
|
// Text-style fraction command has 2 arguments
|
|
let frac = MTFraction()
|
|
let numerator = self.buildInternal(true)
|
|
let denominator = self.buildInternal(true)
|
|
|
|
// Prepend \textstyle to force text mode rendering
|
|
let textStyle = MTMathStyle(style: .text)
|
|
numerator?.insert(textStyle, at: 0)
|
|
denominator?.insert(textStyle, at: 0)
|
|
|
|
frac.numerator = numerator
|
|
frac.denominator = denominator
|
|
return frac;
|
|
} else if command == "binom" {
|
|
// A binom command has 2 arguments
|
|
let frac = MTFraction(hasRule: false)
|
|
frac.numerator = self.buildInternal(true)
|
|
frac.denominator = self.buildInternal(true)
|
|
frac.leftDelimiter = "(";
|
|
frac.rightDelimiter = ")";
|
|
return frac;
|
|
} else if command == "bra" {
|
|
// Dirac bra notation: \bra{psi} -> ⟨psi|
|
|
let inner = MTInner()
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: "langle")
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: "|")
|
|
inner.innerList = self.buildInternal(true)
|
|
return inner
|
|
} else if command == "ket" {
|
|
// Dirac ket notation: \ket{psi} -> |psi⟩
|
|
let inner = MTInner()
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: "|")
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: "rangle")
|
|
inner.innerList = self.buildInternal(true)
|
|
return inner
|
|
} else if command == "braket" {
|
|
// Dirac braket notation: \braket{phi}{psi} -> ⟨phi|psi⟩
|
|
let inner = MTInner()
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: "langle")
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: "rangle")
|
|
// Build the inner content: phi | psi
|
|
let phi = self.buildInternal(true)
|
|
let psi = self.buildInternal(true)
|
|
let content = MTMathList()
|
|
if let phiList = phi {
|
|
for atom in phiList.atoms {
|
|
content.add(atom)
|
|
}
|
|
}
|
|
// Add the | separator
|
|
content.add(MTMathAtom(type: .ordinary, value: "|"))
|
|
if let psiList = psi {
|
|
for atom in psiList.atoms {
|
|
content.add(atom)
|
|
}
|
|
}
|
|
inner.innerList = content
|
|
return inner
|
|
} else if command == "operatorname" || command == "operatorname*" {
|
|
// \operatorname{name} creates a custom operator with proper spacing
|
|
// \operatorname*{name} creates an operator with limits above/below
|
|
let hasLimits = command.hasSuffix("*")
|
|
|
|
// Parse the operator name
|
|
let content = self.buildInternal(true)
|
|
|
|
// Convert the parsed content to a string
|
|
var operatorName = ""
|
|
if let atoms = content?.atoms {
|
|
for atom in atoms {
|
|
operatorName += atom.nucleus
|
|
}
|
|
}
|
|
|
|
if operatorName.isEmpty {
|
|
let errorMessage = "Missing operator name for \\operatorname"
|
|
self.setError(.invalidCommand, message: errorMessage)
|
|
return nil
|
|
}
|
|
|
|
return MTLargeOperator(value: operatorName, limits: hasLimits)
|
|
} else if command == "sqrt" {
|
|
// A sqrt command with one argument
|
|
let rad = MTRadical()
|
|
guard self.hasCharacters else {
|
|
rad.radicand = self.buildInternal(true)
|
|
return rad
|
|
}
|
|
let ch = self.getNextCharacter()
|
|
if (ch == "[") {
|
|
// special handling for sqrt[degree]{radicand}
|
|
rad.degree = self.buildInternal(false, stopChar:"]")
|
|
rad.radicand = self.buildInternal(true)
|
|
} else {
|
|
self.unlookCharacter()
|
|
rad.radicand = self.buildInternal(true)
|
|
}
|
|
return rad;
|
|
} else if command == "left" {
|
|
// Save the current inner while a new one gets built.
|
|
let oldInner = currentInnerAtom
|
|
currentInnerAtom = MTInner()
|
|
currentInnerAtom!.leftBoundary = self.getBoundaryAtom("left")
|
|
if currentInnerAtom!.leftBoundary == nil {
|
|
return nil;
|
|
}
|
|
currentInnerAtom!.innerList = self.buildInternal(false)
|
|
if currentInnerAtom!.rightBoundary == nil {
|
|
// A right node would have set the right boundary so we must be missing the right node.
|
|
let errorMessage = "Missing \\right"
|
|
self.setError(.missingRight, message:errorMessage)
|
|
return nil
|
|
}
|
|
// reinstate the old inner atom.
|
|
let newInner = currentInnerAtom;
|
|
currentInnerAtom = oldInner;
|
|
return newInner;
|
|
} else if command == "overline" {
|
|
// The overline command has 1 arguments
|
|
let over = MTOverLine()
|
|
over.innerList = self.buildInternal(true)
|
|
return over
|
|
} else if command == "underline" {
|
|
// The underline command has 1 arguments
|
|
let under = MTUnderLine()
|
|
under.innerList = self.buildInternal(true)
|
|
return under
|
|
} else if command == "substack" {
|
|
// \substack reads ONE braced argument containing rows separated by \\
|
|
// Similar to how \frac reads {numerator}{denominator}
|
|
|
|
// Read the braced content using standard pattern
|
|
let content = self.buildInternal(true)
|
|
|
|
if content == nil {
|
|
return nil
|
|
}
|
|
|
|
// The content may already be a table if \\ was encountered
|
|
// Check if we got a table from the \\ parsing
|
|
if content!.atoms.count == 1, let tableAtom = content!.atoms.first as? MTMathTable {
|
|
return tableAtom
|
|
}
|
|
|
|
// Otherwise, single row - wrap in table
|
|
var rows = [[MTMathList]]()
|
|
rows.append([content!])
|
|
|
|
var error: NSError? = self.error
|
|
let table = MTMathAtomFactory.table(withEnvironment: nil, rows: rows, error: &error)
|
|
if table == nil && self.error == nil {
|
|
self.error = error
|
|
return nil
|
|
}
|
|
|
|
return table
|
|
} else if command == "begin" {
|
|
let env = self.readEnvironment()
|
|
if env == nil {
|
|
return nil;
|
|
}
|
|
let table = self.buildTable(env: env, firstList:nil, isRow:false)
|
|
return table
|
|
} else if command == "color" {
|
|
// A color command has 2 arguments
|
|
let mathColor = MTMathColor()
|
|
let color = self.readColor()
|
|
if color == nil {
|
|
return nil;
|
|
}
|
|
mathColor.colorString = color!
|
|
mathColor.innerList = self.buildInternal(true)
|
|
return mathColor
|
|
} else if command == "textcolor" {
|
|
// A textcolor command has 2 arguments
|
|
let mathColor = MTMathTextColor()
|
|
let color = self.readColor()
|
|
if color == nil {
|
|
return nil;
|
|
}
|
|
mathColor.colorString = color!
|
|
mathColor.innerList = self.buildInternal(true)
|
|
return mathColor
|
|
} else if command == "colorbox" {
|
|
// A color command has 2 arguments
|
|
let mathColorbox = MTMathColorbox()
|
|
let color = self.readColor()
|
|
if color == nil {
|
|
return nil;
|
|
}
|
|
mathColorbox.colorString = color!
|
|
mathColorbox.innerList = self.buildInternal(true)
|
|
return mathColorbox
|
|
} else if command == "pmod" {
|
|
// A pmod command has 1 argument - creates (mod n)
|
|
let inner = MTInner()
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: "(")
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: ")")
|
|
|
|
let innerList = MTMathList()
|
|
|
|
// Add the "mod" operator (upright text)
|
|
let modOperator = MTMathAtomFactory.atom(forLatexSymbol: "mod")!
|
|
innerList.add(modOperator)
|
|
|
|
// Add medium space between "mod" and argument (6mu)
|
|
let space = MTMathSpace(space: 6.0)
|
|
innerList.add(space)
|
|
|
|
// Parse the argument from braces
|
|
let argument = self.buildInternal(true)
|
|
if let argList = argument {
|
|
innerList.append(argList)
|
|
}
|
|
|
|
inner.innerList = innerList
|
|
return inner
|
|
} else if command == "not" {
|
|
// Handle \not command with lookahead for comprehensive negation support
|
|
let nextCommand = self.peekNextCommand()
|
|
|
|
if let negatedUnicode = Self.notCombinations[nextCommand] {
|
|
self.consumeNextCommand() // Remove base symbol from stream
|
|
return MTMathAtom(type: .relation, value: negatedUnicode)
|
|
} else {
|
|
let errorMessage = "Unsupported \\not\\\(nextCommand) combination"
|
|
self.setError(.invalidCommand, message: errorMessage)
|
|
return nil
|
|
}
|
|
} else if let sizeMultiplier = Self.delimiterSizeCommands[command] {
|
|
// Handle \big, \Big, \bigg, \Bigg and their variants
|
|
let delim = self.readDelimiter()
|
|
if delim == nil {
|
|
let errorMessage = "Missing delimiter for \\\(command)"
|
|
self.setError(.missingDelimiter, message: errorMessage)
|
|
return nil
|
|
}
|
|
let boundary = MTMathAtomFactory.boundary(forDelimiter: delim!)
|
|
if boundary == nil {
|
|
let errorMessage = "Invalid delimiter for \\\(command): \(delim!)"
|
|
self.setError(.invalidDelimiter, message: errorMessage)
|
|
return nil
|
|
}
|
|
|
|
// Create MTInner with explicit delimiter height
|
|
let inner = MTInner()
|
|
|
|
// Determine if this is a left, right, or middle delimiter based on command suffix
|
|
let isLeft = command.hasSuffix("l")
|
|
let isRight = command.hasSuffix("r")
|
|
// let isMiddle = command.hasSuffix("m") // For future use
|
|
|
|
if isLeft {
|
|
inner.leftBoundary = boundary
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: ".")
|
|
} else if isRight {
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: ".")
|
|
inner.rightBoundary = boundary
|
|
} else {
|
|
// For \big, \Big, \bigg, \Bigg and \bigm variants, use the delimiter on both sides
|
|
// but with empty inner content - it's just a sized delimiter
|
|
inner.leftBoundary = boundary
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: ".")
|
|
}
|
|
|
|
inner.innerList = MTMathList()
|
|
inner.delimiterHeight = sizeMultiplier // Store multiplier, typesetter will compute actual height
|
|
|
|
return inner
|
|
} else {
|
|
let errorMessage = "Invalid command \\\(command)"
|
|
self.setError(.invalidCommand, message:errorMessage)
|
|
return nil;
|
|
}
|
|
}
|
|
|
|
mutating func readColor() -> String? {
|
|
if !self.expectCharacter("{") {
|
|
// We didn't find an opening brace, so no env found.
|
|
self.setError(.characterNotFound, message:"Missing {")
|
|
return nil;
|
|
}
|
|
|
|
// Ignore spaces and nonascii.
|
|
self.skipSpaces()
|
|
|
|
// a string of all upper and lower case characters.
|
|
var mutable = ""
|
|
while self.hasCharacters {
|
|
let ch = self.getNextCharacter()
|
|
if ch == "#" || (ch >= "A" && ch <= "Z") || (ch >= "a" && ch <= "z") || (ch >= "0" && ch <= "9") {
|
|
mutable.append(ch) // appendString:[NSString stringWithCharacters:&ch length:1]];
|
|
} else {
|
|
// we went too far
|
|
self.unlookCharacter()
|
|
break;
|
|
}
|
|
}
|
|
|
|
if !self.expectCharacter("}") {
|
|
// We didn't find an closing brace, so invalid format.
|
|
self.setError(.characterNotFound, message:"Missing }")
|
|
return nil;
|
|
}
|
|
return mutable;
|
|
}
|
|
|
|
mutating func skipSpaces() {
|
|
while self.hasCharacters {
|
|
let ch = self.getNextCharacter().utf32Char
|
|
if ch < 0x21 || ch > 0x7E {
|
|
// skip non ascii characters and spaces
|
|
continue;
|
|
} else {
|
|
self.unlookCharacter()
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
static var fractionCommands: [String:[Character]] {
|
|
[
|
|
"over": [],
|
|
"atop" : [],
|
|
"choose" : [ "(", ")"],
|
|
"brack" : [ "[", "]"],
|
|
"brace" : [ "{", "}"]
|
|
]
|
|
}
|
|
|
|
mutating func stopCommand(_ command: String, list:MTMathList, stopChar:Character?) -> MTMathList? {
|
|
if command == "right" {
|
|
if currentInnerAtom == nil {
|
|
let errorMessage = "Missing \\left";
|
|
self.setError(.missingLeft, message:errorMessage)
|
|
return nil;
|
|
}
|
|
currentInnerAtom!.rightBoundary = self.getBoundaryAtom("right")
|
|
if currentInnerAtom!.rightBoundary == nil {
|
|
return nil;
|
|
}
|
|
// return the list read so far.
|
|
return list
|
|
} else if let delims = Self.fractionCommands[command] {
|
|
var frac:MTFraction! = nil;
|
|
if command == "over" {
|
|
frac = MTFraction()
|
|
} else {
|
|
frac = MTFraction(hasRule: false)
|
|
}
|
|
if delims.count == 2 {
|
|
frac.leftDelimiter = String(delims[0])
|
|
frac.rightDelimiter = String(delims[1])
|
|
}
|
|
frac.numerator = list;
|
|
frac.denominator = self.buildInternal(false, stopChar: stopChar)
|
|
if error != nil {
|
|
return nil;
|
|
}
|
|
let fracList = MTMathList()
|
|
fracList.add(frac)
|
|
return fracList
|
|
} else if command == "\\" || command == "cr" {
|
|
if currentEnv != nil {
|
|
// Stop the current list and increment the row count
|
|
currentEnv!.numRows+=1
|
|
return list
|
|
} else {
|
|
// Create a new table with the current list and a default env
|
|
if let table = self.buildTable(env: nil, firstList:list, isRow:true) {
|
|
return MTMathList(atom: table)
|
|
}
|
|
}
|
|
} else if command == "end" {
|
|
if currentEnv == nil {
|
|
let errorMessage = "Missing \\begin";
|
|
self.setError(.missingBegin, message:errorMessage)
|
|
return nil
|
|
}
|
|
let env = self.readEnvironment()
|
|
if env == nil {
|
|
return nil
|
|
}
|
|
if env! != currentEnv!.envName {
|
|
let errorMessage = "Begin environment name \(currentEnv!.envName ?? "(none)") does not match end name: \(env!)"
|
|
self.setError(.invalidEnv, message:errorMessage)
|
|
return nil
|
|
}
|
|
// Finish the current environment.
|
|
currentEnv!.ended = true
|
|
return list
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Applies the modifier to the atom. Returns true if modifier applied.
|
|
mutating func applyModifier(_ modifier:String, atom:MTMathAtom?) -> Bool {
|
|
if modifier == "limits" {
|
|
if atom?.type != .largeOperator {
|
|
let errorMessage = "Limits can only be applied to an operator."
|
|
self.setError(.invalidLimits, message:errorMessage)
|
|
} else {
|
|
let op = atom as! MTLargeOperator
|
|
op.limits = true
|
|
}
|
|
return true
|
|
} else if modifier == "nolimits" {
|
|
if atom?.type != .largeOperator {
|
|
let errorMessage = "No limits can only be applied to an operator."
|
|
self.setError(.invalidLimits, message:errorMessage)
|
|
} else {
|
|
let op = atom as! MTLargeOperator
|
|
op.limits = false
|
|
}
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
mutating func setError(_ code:MTParseErrors, message:String) {
|
|
// Only record the first error.
|
|
if error == nil {
|
|
error = NSError(domain: MTParseError, code: code.rawValue, userInfo: [ NSLocalizedDescriptionKey : message ])
|
|
}
|
|
}
|
|
|
|
mutating func atom(forCommand command: String) -> MTMathAtom? {
|
|
if let atom = MTMathAtomFactory.atom(forLatexSymbol: command) {
|
|
return atom
|
|
}
|
|
if let accent = MTMathAtomFactory.accent(withName: command) {
|
|
accent.innerList = self.buildInternal(true)
|
|
return accent
|
|
} else if command == "frac" {
|
|
let frac = MTFraction()
|
|
frac.numerator = self.buildInternal(true)
|
|
frac.denominator = self.buildInternal(true)
|
|
return frac
|
|
} else if command == "cfrac" {
|
|
let frac = MTFraction()
|
|
frac.isContinuedFraction = true
|
|
|
|
// Parse optional alignment parameter [l], [r], [c]
|
|
skipSpaces()
|
|
if hasCharacters && string[currentCharIndex] == "[" {
|
|
_ = getNextCharacter() // consume '['
|
|
if hasCharacters {
|
|
let alignmentChar = getNextCharacter()
|
|
if alignmentChar == "l" || alignmentChar == "r" || alignmentChar == "c" {
|
|
frac.alignment = String(alignmentChar)
|
|
}
|
|
}
|
|
// Consume closing ']'
|
|
if hasCharacters && string[currentCharIndex] == "]" {
|
|
_ = getNextCharacter()
|
|
}
|
|
}
|
|
|
|
frac.numerator = self.buildInternal(true)
|
|
frac.denominator = self.buildInternal(true)
|
|
return frac
|
|
} else if command == "dfrac" {
|
|
// Display-style fraction command has 2 arguments
|
|
let frac = MTFraction()
|
|
let numerator = self.buildInternal(true)
|
|
let denominator = self.buildInternal(true)
|
|
|
|
// Prepend \displaystyle to force display mode rendering
|
|
let displayStyle = MTMathStyle(style: .display)
|
|
numerator?.insert(displayStyle, at: 0)
|
|
denominator?.insert(displayStyle, at: 0)
|
|
|
|
frac.numerator = numerator
|
|
frac.denominator = denominator
|
|
return frac
|
|
} else if command == "tfrac" {
|
|
// Text-style fraction command has 2 arguments
|
|
let frac = MTFraction()
|
|
let numerator = self.buildInternal(true)
|
|
let denominator = self.buildInternal(true)
|
|
|
|
// Prepend \textstyle to force text mode rendering
|
|
let textStyle = MTMathStyle(style: .text)
|
|
numerator?.insert(textStyle, at: 0)
|
|
denominator?.insert(textStyle, at: 0)
|
|
|
|
frac.numerator = numerator
|
|
frac.denominator = denominator
|
|
return frac
|
|
} else if command == "binom" {
|
|
let frac = MTFraction(hasRule: false)
|
|
frac.numerator = self.buildInternal(true)
|
|
frac.denominator = self.buildInternal(true)
|
|
frac.leftDelimiter = "("
|
|
frac.rightDelimiter = ")"
|
|
return frac
|
|
} else if command == "bra" {
|
|
// Dirac bra notation: \bra{psi} -> ⟨psi|
|
|
let inner = MTInner()
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: "langle")
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: "|")
|
|
inner.innerList = self.buildInternal(true)
|
|
return inner
|
|
} else if command == "ket" {
|
|
// Dirac ket notation: \ket{psi} -> |psi⟩
|
|
let inner = MTInner()
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: "|")
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: "rangle")
|
|
inner.innerList = self.buildInternal(true)
|
|
return inner
|
|
} else if command == "braket" {
|
|
// Dirac braket notation: \braket{phi}{psi} -> ⟨phi|psi⟩
|
|
let inner = MTInner()
|
|
inner.leftBoundary = MTMathAtomFactory.boundary(forDelimiter: "langle")
|
|
inner.rightBoundary = MTMathAtomFactory.boundary(forDelimiter: "rangle")
|
|
let phi = self.buildInternal(true)
|
|
let psi = self.buildInternal(true)
|
|
let content = MTMathList()
|
|
if let phiList = phi {
|
|
for atom in phiList.atoms {
|
|
content.add(atom)
|
|
}
|
|
}
|
|
content.add(MTMathAtom(type: .ordinary, value: "|"))
|
|
if let psiList = psi {
|
|
for atom in psiList.atoms {
|
|
content.add(atom)
|
|
}
|
|
}
|
|
inner.innerList = content
|
|
return inner
|
|
} else if command == "operatorname" || command == "operatorname*" {
|
|
// \operatorname{name} creates a custom operator with proper spacing
|
|
// \operatorname*{name} creates an operator with limits above/below
|
|
let hasLimits = command.hasSuffix("*")
|
|
|
|
let content = self.buildInternal(true)
|
|
var operatorName = ""
|
|
if let atoms = content?.atoms {
|
|
for atom in atoms {
|
|
operatorName += atom.nucleus
|
|
}
|
|
}
|
|
if operatorName.isEmpty {
|
|
self.setError(.invalidCommand, message: "Missing operator name for \\operatorname")
|
|
return nil
|
|
}
|
|
return MTLargeOperator(value: operatorName, limits: hasLimits)
|
|
} else if command == "sqrt" {
|
|
let rad = MTRadical()
|
|
guard self.hasCharacters else {
|
|
rad.radicand = self.buildInternal(true)
|
|
return rad
|
|
}
|
|
let char = self.getNextCharacter()
|
|
if char == "[" {
|
|
rad.degree = self.buildInternal(false, stopChar: "]")
|
|
rad.radicand = self.buildInternal(true)
|
|
} else {
|
|
self.unlookCharacter()
|
|
rad.radicand = self.buildInternal(true)
|
|
}
|
|
return rad
|
|
} else if command == "left" {
|
|
let oldInner = self.currentInnerAtom
|
|
self.currentInnerAtom = MTInner()
|
|
self.currentInnerAtom?.leftBoundary = self.getBoundaryAtom("left")
|
|
if self.currentInnerAtom?.leftBoundary == nil {
|
|
return nil
|
|
}
|
|
self.currentInnerAtom!.innerList = self.buildInternal(false)
|
|
if self.currentInnerAtom?.rightBoundary == nil {
|
|
self.setError(.missingRight, message: "Missing \\right")
|
|
return nil
|
|
}
|
|
let newInner = self.currentInnerAtom
|
|
currentInnerAtom = oldInner
|
|
return newInner
|
|
} else if command == "overline" {
|
|
let over = MTOverLine()
|
|
over.innerList = self.buildInternal(true)
|
|
|
|
return over
|
|
} else if command == "underline" {
|
|
let under = MTUnderLine()
|
|
under.innerList = self.buildInternal(true)
|
|
|
|
return under
|
|
} else if command == "begin" {
|
|
if let env = self.readEnvironment() {
|
|
// Check if this is a starred matrix environment and read optional alignment
|
|
var alignment: MTColumnAlignment? = nil
|
|
if env.hasSuffix("*") {
|
|
alignment = self.readOptionalAlignment()
|
|
if self.error != nil {
|
|
return nil
|
|
}
|
|
}
|
|
|
|
let table = self.buildTable(env: env, alignment: alignment, firstList: nil, isRow: false)
|
|
return table
|
|
} else {
|
|
return nil
|
|
}
|
|
} else if command == "color" {
|
|
// A color command has 2 arguments
|
|
let mathColor = MTMathColor()
|
|
mathColor.colorString = self.readColor()!
|
|
mathColor.innerList = self.buildInternal(true)
|
|
return mathColor
|
|
} else if command == "colorbox" {
|
|
// A color command has 2 arguments
|
|
let mathColorbox = MTMathColorbox()
|
|
mathColorbox.colorString = self.readColor()!
|
|
mathColorbox.innerList = self.buildInternal(true)
|
|
return mathColorbox
|
|
} else {
|
|
self.setError(.invalidCommand, message: "Invalid command \\\(command)")
|
|
return nil
|
|
}
|
|
}
|
|
|
|
mutating func readEnvironment() -> String? {
|
|
if !self.expectCharacter("{") {
|
|
// We didn't find an opening brace, so no env found.
|
|
self.setError(.characterNotFound, message: "Missing {")
|
|
return nil
|
|
}
|
|
|
|
self.skipSpaces()
|
|
let env = self.readString()
|
|
|
|
if !self.expectCharacter("}") {
|
|
// We didn"t find an closing brace, so invalid format.
|
|
self.setError(.characterNotFound, message: "Missing }")
|
|
return nil;
|
|
}
|
|
return env
|
|
}
|
|
|
|
/// Reads optional alignment parameter for starred matrix environments: [r], [l], or [c]
|
|
mutating func readOptionalAlignment() -> MTColumnAlignment? {
|
|
self.skipSpaces()
|
|
|
|
// Check if there's an opening bracket
|
|
guard hasCharacters && string[currentCharIndex] == "[" else {
|
|
return nil
|
|
}
|
|
|
|
_ = getNextCharacter() // consume '['
|
|
self.skipSpaces()
|
|
|
|
guard hasCharacters else {
|
|
self.setError(.characterNotFound, message: "Missing alignment specifier after [")
|
|
return nil
|
|
}
|
|
|
|
let alignChar = getNextCharacter()
|
|
let alignment: MTColumnAlignment?
|
|
|
|
switch alignChar {
|
|
case "l":
|
|
alignment = .left
|
|
case "c":
|
|
alignment = .center
|
|
case "r":
|
|
alignment = .right
|
|
default:
|
|
self.setError(.invalidEnv, message: "Invalid alignment specifier: \(alignChar). Must be l, c, or r")
|
|
return nil
|
|
}
|
|
|
|
self.skipSpaces()
|
|
|
|
if !self.expectCharacter("]") {
|
|
self.setError(.characterNotFound, message: "Missing ] after alignment specifier")
|
|
return nil
|
|
}
|
|
|
|
return alignment
|
|
}
|
|
|
|
func MTAssertNotSpace(_ ch: Character) {
|
|
assert(ch >= "\u{21}" && ch <= "\u{7E}", "Expected non-space character \(ch)")
|
|
}
|
|
|
|
mutating func buildTable(env: String?, alignment: MTColumnAlignment? = nil, firstList: MTMathList?, isRow: Bool) -> MTMathAtom? {
|
|
// Save the current env till an new one gets built.
|
|
let oldEnv = self.currentEnv
|
|
|
|
currentEnv = MTEnvProperties(name: env, alignment: alignment)
|
|
|
|
var currentRow = 0
|
|
var currentCol = 0
|
|
|
|
var rows = [[MTMathList]]()
|
|
rows.append([MTMathList]())
|
|
if firstList != nil {
|
|
rows[currentRow].append(firstList!)
|
|
if isRow {
|
|
currentEnv!.numRows+=1
|
|
currentRow+=1
|
|
rows.append([MTMathList]())
|
|
} else {
|
|
currentCol+=1
|
|
}
|
|
}
|
|
while !currentEnv!.ended && self.hasCharacters {
|
|
let list = self.buildInternal(false)
|
|
if list == nil {
|
|
// If there is an error building the list, bail out early.
|
|
return nil
|
|
}
|
|
rows[currentRow].append(list!)
|
|
currentCol+=1
|
|
if currentEnv!.numRows > currentRow {
|
|
currentRow = currentEnv!.numRows
|
|
rows.append([MTMathList]())
|
|
currentCol = 0
|
|
}
|
|
}
|
|
|
|
if !currentEnv!.ended && currentEnv!.envName != nil {
|
|
self.setError(.missingEnd, message: "Missing \\end")
|
|
return nil
|
|
}
|
|
|
|
var error:NSError? = self.error
|
|
let table = MTMathAtomFactory.table(withEnvironment: currentEnv?.envName, alignment: currentEnv?.alignment, rows: rows, error: &error)
|
|
if table == nil && self.error == nil {
|
|
self.error = error
|
|
return nil
|
|
}
|
|
self.currentEnv = oldEnv
|
|
return table
|
|
}
|
|
|
|
mutating func getBoundaryAtom(_ delimiterType: String) -> MTMathAtom? {
|
|
let delim = self.readDelimiter()
|
|
if delim == nil {
|
|
let errorMessage = "Missing delimiter for \\\(delimiterType)"
|
|
self.setError(.missingDelimiter, message:errorMessage)
|
|
return nil
|
|
}
|
|
let boundary = MTMathAtomFactory.boundary(forDelimiter: delim!)
|
|
if boundary == nil {
|
|
let errorMessage = "Invalid delimiter for \(delimiterType): \(delim!)"
|
|
self.setError(.invalidDelimiter, message:errorMessage)
|
|
return nil
|
|
}
|
|
return boundary
|
|
}
|
|
|
|
mutating func readDelimiter() -> String? {
|
|
self.skipSpaces()
|
|
while self.hasCharacters {
|
|
let char = self.getNextCharacter()
|
|
MTAssertNotSpace(char)
|
|
if char == "\\" {
|
|
let command = self.readCommand()
|
|
if command == "|" {
|
|
return "||"
|
|
}
|
|
return command
|
|
} else {
|
|
return String(char)
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
mutating func readCommand() -> String {
|
|
let singleChars = "{}$#%_| ,>;!\\"
|
|
if self.hasCharacters {
|
|
let char = self.getNextCharacter()
|
|
if let _ = singleChars.firstIndex(of: char) {
|
|
return String(char)
|
|
} else {
|
|
self.unlookCharacter()
|
|
}
|
|
}
|
|
return self.readString()
|
|
}
|
|
|
|
mutating func readString() -> String {
|
|
// a string of all upper and lower case characters (and asterisks for starred environments)
|
|
var output = ""
|
|
while self.hasCharacters {
|
|
let char = self.getNextCharacter()
|
|
if char.isLowercase || char.isUppercase || char == "*" {
|
|
output.append(char)
|
|
} else {
|
|
self.unlookCharacter()
|
|
break
|
|
}
|
|
}
|
|
return output
|
|
}
|
|
}
|